#include<bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define pb push_back
#define int long long
const int N=1e5+5;
const int mod=1e9+7;
int dp[N];
int d[N],x[N];
int sv[500][500];
vector<int>del[N];
signed main(){
int n;
cin>>n;
for(int i=1;i<=n;i++)cin>>d[i]>>x[i];
// x udaa d eer userne
int B=sqrt(N);
dp[1]=1;
for(int i=1;i<=n;i++){
for(int j=1;j<B;j++){
(dp[i]+=sv[j][i%j])%=mod;
}
for(auto idx:del[i]){
(sv[d[idx]][idx%d[idx]]-=dp[idx]-mod)%=mod;
}
if(x[i]==0 or d[i]==0)continue;
if( d[i]>=B){
for(int j=1;j<=x[i];j++){
if(i+ d[i]*j<=n){
(dp[i+d[i]*j]+=dp[i])%=mod;
}
else break;
}
}
else{
(sv[d[i]][i%d[i]]+=dp[i]);
if(i+d[i]*x[i]<=n)del[i+d[i]*x[i]].pb(i);
}
}
int ans=0;
for(int i=1;i<=n;i++)(ans+=dp[i])%=mod;
cout<<ans;
}
